class Solution:
    def kthSmallest(self, root, k):
        """
        :type root: TreeNode
        :type k: int
        :rtype: int
        """
        def inorder(r):
            return inorder(r.left) + [r.val] + inorder(r.right) if r else []
        return inorder(root)[k - 1]
'''
二叉搜索树的中序遍历就是顺序的左中右就是从小到大, 直接返回即可
'''
a = [1,2,3] + [4,5,6]
print(a)